Waveguide-based light sources with dynamic beam shaping

ABSTRACT

Luminaires are described herein employing waveguides and associated architectures for dynamic alteration of illuminance distribution patterns. The waveguide includes a light extraction component. The waveguide transmits light from a light source to the light extraction component by total internal reflection (TIR). The light extraction component includes one or more reversibly moveable surfaces for altering illuminance distribution patterns of the luminaire in response to one or more forces applied to the light extraction component by a force application assembly of the luminaire.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent application Ser. No. 17/481,727, filed Sep. 22, 2021. U.S. patent application Ser. No. 17/481,727 is continuation-in-part of U.S. patent application Ser. No. 17/100,261, filed Nov. 20, 2020 (now U.S. Pat. No. 11,372,156, issued Jun. 28, 2022), which is a continuation of U.S. patent application Ser. No. 16/703,125, filed Dec. 4, 2019 (now U.S. Pat. No. 10,890,714, issued Jan. 12, 2021), which is a continuation of U.S. patent application Ser. No. 15/587,442, filed May 5, 2017 (now U.S. Pat. No. 10,527,785, issued Jan. 7, 2020), which claims priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application Ser. No. 62/333,000, filed on May 6, 2016, all of which are incorporated herein by reference in their entirety.

U.S. patent application Ser. No. 17/481,727 is also a continuation-in-part of U.S. patent application Ser. No. 15/186,222, filed Jun. 17, 2016 (now U.S. Pat. No. 11,156,764, issued Oct. 26, 2021), the contents of which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present invention relates to lighting assemblies and, in particular, to lighting assemblies employing bonded optical elements, waveguides, and associated architectures for dynamic alteration of illuminance distribution patterns.

BACKGROUND

An optical waveguide mixes and directs light emitted by one or more light sources, such as one or more light emitting diodes (LEDs). A typical optical waveguide includes three main components: one or more coupling elements, one or more distribution elements, and one or more extraction elements. The coupling component(s) direct light into the distribution element(s), and condition the light to interact with the subsequent components. The one or more distribution elements control how light flows through the waveguide and is dependent on the waveguide geometry and material. The extraction element(s) determine how light is removed by controlling where and in what direction the light exits the waveguide.

In order for an extraction element to remove light from the waveguide, the light must first contact the feature comprising the element. By appropriately shaping waveguide surfaces, one can control the flow of light across the extraction feature(s). Selecting the spacing, shape and other characteristic(s) of the extraction elements affects the appearance of the waveguide and its resulting angular distribution of emitted light and efficiency.

However, waveguide shape and extraction feature characteristics are generally fixed, thereby producing a static illuminance distribution pattern of the lighting device. Alteration of the illuminance distribution pattern, therefore, requires the lighting device to be adjusted via one or more means external to the device, such as by an individual manually moving, adding or removing optical element(s) of the lighting device. Such external modification can be time consuming and precludes real-time adjustments in response to changes in the lighting environment.

In addition, optical systems can present very limited bonding area between individual components due to optical performance requirements. For many lighting applications, extraction elements are bonded to the waveguide body with adhesive. The amount of adhesive is limited to maintain desired optical performance. Light extraction elements can be individually placed and bonded to the waveguide body. Alternatively, light extraction elements may be part of an extractor plate. Given the limited amount of adhesive and small bonded area, flexural loads or other stresses applied to the waveguide body can work to delaminate or de-bond extraction elements.

FIG. 1 , for example, illustrates de-bonding of extraction elements 2 from the waveguide body 4 in response to a flexural load 6 applied to the waveguide body 4. In the example of FIG. 1 , the extraction elements 2 are part of an extractor plate 8. The flexural load can apply tensile stress and/or shear stress resulting in the de-bonding.

SUMMARY

In view of these disadvantages, luminaires are described herein employing waveguides and associated architectures for dynamic alteration of illuminance distribution patterns. In one aspect, a luminaire described herein comprises a waveguide body and light sources having differing angular positions relative to the waveguide body for altering illuminance distribution patterns of the luminaire according to one or more activation patterns of the light sources. The differing angular positions can be located at the perimeter of the waveguide body and/or at one or more internal locations of the waveguide body. Moreover, the light sources can be coupled into a side edge of the waveguide body and/or at internal coupling cavities. Depending on the embodiment, the activation pattern of the light sources can alter the illuminance distribution pattern of the luminaire azimuthally, longitudinally, or various combinations thereof.

In another aspect, a luminaire described herein comprises a waveguide body and light extraction component(s) on and/or in the waveguide body, wherein the light extraction component(s) include one or more reversibly moveable surfaces for altering illuminance distribution patterns of the luminaire. As detailed further herein, forces can be applied mechanically, electrically and/or magnetically to reversibly moveable surfaces of the light extraction component(s).

In a further aspect, luminaires of hybrid construction are described, which include at least one waveguide in conjunction with one or more conventional optics. In some embodiments, for example, a luminaire comprises at least one light source and a waveguide including a waveguide body and light extraction component(s) on and/or in the waveguide body. At least one optic external to the waveguide is arranged to receive at least a portion of light from the waveguide and/or a portion of light directly from the light source. The external optic can be a reflector or lens.

Importantly, elements and features of luminaires described herein can be combined in any number of ways to provide luminaires of various construction and design. In non-limiting embodiments, for example, a luminaire of hybrid construction can incorporate waveguide light extraction components including one or more reversibly moveable surfaces for altering illuminance distribution patterns of the luminaire. The hybrid luminaire may also include selectable banks of LEDs having differing angular positions relative to one or more waveguide bodies, such as stacked waveguides and/or waveguides having lateral arrangement. For example, the hybrid luminaire can employ banks of LEDs having differing angular positions along the waveguide body perimeter for steering an azimuthal component of illuminance distribution patterns of the luminaire in conjunction with the light extraction component. In additional embodiments, a luminaire having a non-hybrid construction can employ a waveguide light extraction component including one or more reversibly moveable surfaces in conjunction with radial spacing of light sources along the waveguide body perimeter for steering an azimuthal component of illuminance distribution patterns of the luminaire.

Methods of dynamic lighting are also provided herein. In some embodiments, a method of dynamic lighting comprises providing a luminaire including a waveguide body and light extraction component(s), wherein light sources of the luminaire have differing angular positions relative to the waveguide body. An illuminance distribution pattern of the luminaire is altered by selectively lighting one or more of the light sources. For example, azimuthal and/or longitudinal components of the luminaire illuminance distribution patterns can be steered by selectively lighting one or more of the light sources.

In another aspect, a method of dynamic lighting includes providing a luminaire comprising one or more light sources, a waveguide body and light extraction component(s) on and/or in the waveguide body, wherein the light extraction component(s) include one or more reversibly moveable surfaces. An illuminance distribution pattern of the luminaire is altered by application of one or more forces to the reversibly moveable surfaces.

In addition, bonded assemblies are described herein comprising one or more reinforcement members reducing deflection of the assemblies under applied flexural loads, wherein the reinforcement members do not materially interfere with the functionality of the bonded assemblies. In one aspect, waveguide assemblies are provided. A waveguide assembly, in some embodiments, comprises a waveguide body and light extraction elements bonded to the waveguide body, wherein at least one reinforcement member is coupled to the waveguide assembly at one or more locations to reduce deflection of the waveguide assembly under an applied flexural load. As detailed further herein, the light extraction elements can be part of a light extractor plate. Alternatively, the light extraction elements are not part of a light extractor plate and are independently arranged on one or more surfaces of the waveguide body.

In another aspect, bonded assemblies comprising surface features are described herein. An assembly, in some embodiments, comprises a plurality of discrete surface features bonded to a first plate, wherein at least one reinforcement member is coupled to the assembly at one or more locations to reduce deflection of the assembly under an applied flexural load while not altering the surface features and/or function of the assembly. In some embodiments, the surface features are also associated with a second plate resulting in bonding of the first plate and the second plate via the surface features.

These and other embodiments are described further in the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

FIG. 1 illustrates de-bonding of extraction elements from a waveguide body in response to a flexural load applied to the waveguide body.

FIG. 2 illustrates a luminaire having multiple illuminance distribution patterns according to some embodiments.

FIGS. 3A-3F illustrate varying illuminance distribution patterns from a set of luminaires to direct light to desired areas of a conference room according to some embodiments.

FIGS. 4A-4C illustrate luminaires comprising a waveguide body and light sources having differing angular positions relative to the waveguide body according to some embodiments.

FIGS. 5A and 5B illustrate luminaires comprising a waveguide body and light sources having differing angular positions relative to the waveguide body according to some embodiments.

FIG. 6 illustrates a luminaire comprising a waveguide body and light sources having differing radial angular positions relative to the waveguide body according to some embodiments.

FIGS. 7A-7C illustrate geometry and features of a light extraction element according to some embodiments.

FIGS. 8A and 8B illustrate geometry and features of a light extraction element according to some embodiments.

FIGS. 9A and 9B illustrate geometry and features of a light extraction element according to some embodiments.

FIG. 10 is a fragmentary perspective view of a light extraction component of a waveguide comprising an array of light extraction elements on a substrate or film according to some embodiments.

FIG. 11 is a fragmentary perspective view of a light extraction component of a waveguide comprising parallel protrusions of light extraction elements according to some embodiments.

FIG. 12 is a fragmentary perspective view of a light extraction component of a waveguide comprising an array of light extraction elements on a substrate or film according to some embodiments.

FIG. 13 is a fragmentary elevational view of an extraction film comprising a substrate and light extraction elements according to some embodiments.

FIGS. 14-16 are perspective views of prismatic shaped light extraction elements according to some embodiments.

FIG. 17 illustrates a plan view of a luminaire wherein spacing of the light sources matches the polygonal geometry of the array of light extraction elements.

FIG. 18 provides illuminance distribution patterns of the luminaire of FIG. 17 illustrating azimuthal steering according to some embodiments.

FIG. 19 illustrates a plan view of a luminaire wherein spacing of the light sources does not match the polygonal geometry of the array of light extraction elements.

FIG. 20 provides illuminance distribution patterns of the luminaire of FIG. 19 illustrating azimuthal steering according to some embodiments.

FIG. 21 illustrates an exploded view of a luminaire employing dynamic light extraction elements according to some embodiments.

FIG. 22 illustrates a fragmentary cross-sectional view of the luminaire of FIG. 21 .

FIG. 23 illustrates an assembled luminaire including a fluidic force application assembly comprising a pump, fluid channels and cavities for application of fluid pressure to reversibly moveable surfaces of light extraction elements according to some embodiments.

FIGS. 24A-24C illustrate fragmentary views of responses of a reversibly moveable surface of a light extraction element to various fluid pressures applied by a force application assembly according to some embodiments.

FIG. 25A illustrates an array of convex light extraction elements produced in response to application of positive fluid pressure to reversibly moveable surfaces of the light extraction elements.

FIG. 25B illustrates an array of concave light extraction elements produced in response to application of negative fluid pressure to reversibly moveable surfaces of the light extraction elements.

FIG. 26 illustrates a fragmentary cross-sectional view of a waveguide body incorporating fluid flow channels and cavities according to some embodiments.

FIGS. 27A-27C illustrate fragmentary views of responses of a reversibly moveable surface of a light extraction element to various fluid pressures applied by a force application assembly according to some embodiments.

FIG. 28 illustrates extraction lens constructions according to some embodiments.

FIG. 29 illustrates changes in illuminance distribution patterns of a luminaire as a function of radius of hemispherical light extraction elements according to some embodiments.

FIG. 30 illustrates alteration to the illuminance distribution patterns of FIG. 29 when a specular backside reflector is added to the luminaire construction.

FIG. 31 illustrates changes in illuminance distribution patterns of a luminaire as a function of radius of concave light extraction elements according to some embodiments.

FIG. 32 illustrates alteration to the illuminance distribution patterns of FIG. 31 when a specular backside reflector is added to the luminaire construction.

FIG. 33 illustrates one embodiment of a luminaire comprising a waveguide and optic external to the waveguide.

FIGS. 34A and 34B illustrate initiation and progression, respectively, of extraction element de-bonding according to some embodiments.

FIG. 35 illustrates an extractor plate bonded to a waveguide body according to some embodiments described herein.

FIG. 36 illustrates multiple extractor plates bonded to a light emitting surface of a waveguide body according to some embodiments.

FIG. 37A illustrates a cross-sectional view of a reinforcing frame surrounding a light emission region of a waveguide assembly according to some embodiments.

FIG. 37B illustrates a top plan view of a reinforcing frame coupled to the waveguide assembly according to some embodiments.

FIG. 37C illustrates a screw or bolt assembly coupling the reinforcing plate to the waveguide body according to some embodiments.

FIG. 38 illustrates reinforcing frames coupled to the extractor plate and waveguide assembly according to some embodiments described herein.

FIG. 39 illustrates a clamping frame coupled to a waveguide assembly according to some embodiments described herein.

FIG. 40 illustrates mechanical coupling of reinforcement elements to a waveguide body according to some embodiments.

FIG. 41 illustrates application of an adhesive between an extractor plate and waveguide body according to some embodiments.

FIG. 42 illustrates a three-point bend apparatus employed to evaluate reinforced waveguide assemblies described herein.

FIG. 43 illustrates a waveguide assembly comprising a reinforcing frame coupled thereto, wherein LEDs are arranged at edges of the waveguide body according to some embodiments.

FIG. 44 illustrates a sectional view of the waveguide assembly and reinforcing frame of FIG. 43 .

FIG. 45 illustrates a top view of the corner assembly of FIG. 44 .

FIG. 46 illustrates the corner assembly of FIG. 45 wherein a top plate encloses the corner assembly according to some embodiments.

FIG. 47 illustrates integration of the reinforced waveguide assembly into a luminaire construction according to some embodiments.

DETAILED DESCRIPTION

Embodiments described herein can be understood more readily by reference to the following detailed description and examples and their previous and following descriptions. Elements, apparatus and methods described herein, however, are not limited to the specific embodiments presented in the detailed description and examples. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

It will be understood that when an element such as a layer, region or substrate is referred to as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.

Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” or “top” or “bottom” may be used herein to describe a relationship of one element, layer or region to another element, layer or region as illustrated in the figures. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Unless otherwise expressly stated, comparative, quantitative terms such as “less” and “greater”, are intended to encompass the concept of equality. As an example, “less” can mean not only “less” in the strictest mathematical sense, but also, “less than or equal to.”

The terms “LED” and “LED device” as used herein may refer to any solid-state light emitter. The terms “solid state light emitter” or “solid state emitter” may include a light emitting diode, laser diode, organic light emitting diode, and/or other semiconductor device which includes one or more semiconductor layers, which may include silicon, silicon carbide, gallium nitride and/or other semiconductor materials, a substrate which may include sapphire, silicon, silicon carbide and/or other microelectronic substrates, and one or more contact layers which may include metal and/or other conductive materials. A solid-state lighting device produces light (ultraviolet, visible, or infrared) by exciting electrons across the band gap between a conduction band and a valence band of a semiconductor active (light-emitting) layer, with the electron transition generating light at a wavelength that depends on the band gap. Thus, the color (wavelength) of the light emitted by a solid-state emitter depends on the materials of the active layers thereof. In various embodiments, solid-state light emitters may have peak wavelengths in the visible range and/or be used in combination with lumiphoric materials having peak wavelengths in the visible range. Multiple solid state light emitters and/or multiple lumiphoric materials (i.e., in combination with at least one solid state light emitter) may be used in a single device, such as to produce light perceived as white or near white in character. In certain embodiments, the aggregated output of multiple solid-state light emitters and/or lumiphoric materials may generate warm white light output having a color temperature range of from about 1200K to about 5700K.

Solid state light emitters may be used individually or in combination with one or more lumiphoric materials (e.g., phosphors, scintillators, lumiphoric inks) and/or optical elements to generate light at a peak wavelength, or of at least one desired perceived color (including combinations of colors that may be perceived as white). Inclusion of lumiphoric (also called ‘luminescent’) materials in lighting devices as described herein may be accomplished by direct coating on solid state light emitter, adding such materials to encapsulants, adding such materials to lenses, by embedding or dispersing such materials within lumiphor support elements, and/or coating such materials on lumiphor support elements. Other materials, such as light scattering elements (e.g., particles) and/or index matching materials, may be associated with a lumiphor, a lumiphor binding medium, or a lumiphor support element that may be spatially segregated from a solid state emitter.

Prior luminaire architectures are generally limited by static illuminance distribution patterns, thereby precluding such architectures from effectively responding to changes in the lighting environment. In view of this significant disadvantage, architectures are described herein offering multiple illuminance distribution patterns from a single luminaire. Accordingly, illuminance distribution patterns from the luminaire can be varied or altered in response to changing lighting conditions and/or requirements.

FIG. 2 generally illustrates the concept of multiple illuminance distribution patterns from a single luminaire. As illustrated in FIG. 2 , the luminaire 10 offers at least three different illuminance distribution patterns P1, P2, P3. Various structural features of the luminaire can be dynamically varied to provide the desired illuminance distribution pattern according to the requirements of a specific lighting environment. In some embodiments, a single structural feature is dynamically altered by the luminaire to provide the desired illuminance distribution pattern. Alternatively, multiple structural features can be varied in concert by the luminaire to provide the desired illuminance distribution pattern. As described further herein, the luminaire architectures can employ one or more light sources in conjunction with at least one waveguide to achieve multiple illuminance distribution patterns. For example, a luminaire can comprise multiple LEDs or banks of LEDs having differing angular positions relative to the waveguide, such differing positions located on the waveguide perimeter and/or waveguide interior. The LEDs can be selectively lit or switched to provide different illuminance distribution patterns in conjunction with the waveguide. Referring to FIG. 2 , the luminaire 10 can comprise several banks of LEDs. The illuminance distribution pattern P1, P2 or P3 produced can be dependent on which bank of LEDs or combination of LED banks is providing light into waveguide.

Luminaires described herein are not limited to a single waveguide and can incorporate multiple waveguides in various configurations to achieve a variety of illuminance distribution patterns from a single luminaire. In some embodiments, waveguides having differing light extraction features and/or patterns are arranged in a lateral format. Alternatively, differing waveguides can have a vertical or stacked configuration. The waveguides can provide illuminance distributions independent of one another, such as one waveguide providing uplighting and another waveguide providing downlighting.

In other embodiments, multiple waveguides of a luminaire can work in concert to provide a cumulative illuminance distribution pattern. Moreover, multiple waveguides of a luminaire can share a single LED source. Alternatively, each waveguide can have a dedicated LED source. In such embodiments, the dedicated LED sources can be selectively lit to provide a variety of illuminance distribution patterns. Additionally, dedicated LED sources can have differing emission characteristics enabling waveguides of the luminaire to provide lighting of different color, color temperature and/or color rendering index.

The waveguide structure itself can also be dynamically altered to provide differing illuminance distribution patterns. In some embodiments, light extraction features of the waveguide are altered, resulting in changes to the illuminance distribution pattern. For example, the profile and/or pattern of light extraction elements can be varied to provide differing illuminance distribution patterns. As described further herein, changes to profile and/or pattern of light extraction elements can be reversible and administered in real-time. Structural alterations to light extraction elements of the waveguide can also be combined with any of the foregoing features, including LED switching, LED angular positioning and use of multiple waveguides, to alter illuminance distribution patterns of the luminaire.

In an additional aspect, optics external to the waveguide can be employed to alter illuminance distribution patterns of a luminaire. One or more external optics, for example, can be positioned to redirect at least a portion of light exiting the waveguide. External optic(s) can also be positioned to receive light directly from one or more light sources of the luminaire. External optic(s) can be combined with any of the foregoing features for providing multiple illuminance distribution patterns from a single luminaire, including LED switching and spacing, use of multiple waveguides and dynamic alteration of waveguide structural elements.

The ability to dynamically alter illuminance distributions enables luminaires described herein to find application in a variety of lighting environments. For example, luminaires can find application in home, office or retail lighting wherein the illuminance distribution is specifically tailored to direct light where needed and minimize light where it is not. In such applications, illuminance distribution patterns can be based on real-time sensing of occupancy, occupant position, time of day and/or window number and positioning.

FIGS. 3A-3F illustrate altering illuminance distribution patterns of luminaires to direct light to the desired areas of a conference room according to some embodiments. Luminaires described herein may also find application in architectural lighting and/or dynamic street lighting permitting real-time adjustments to illuminance distributions to match various conditions including roadway occupancy, weather and ambient lighting conditions.

The foregoing concepts and combinations thereof are implemented and further illustrated in the following sections detailing azimuthal and/or longitudinal beam alteration, waveguides with dynamic light extraction elements and luminaires of hybrid construction comprising waveguides and external or secondary optics.

I. Azimuthal/Longitudinal Beam Alteration

In one aspect, a luminaire described herein comprises a waveguide body and light sources having differing angular positions relative to the waveguide body for altering illuminance distribution patterns of the luminaire according to one or more activation patterns of the light sources. Depending on the embodiment, the activation pattern of the light sources can alter the illuminance distribution pattern of the luminaire azimuthally, longitudinally, or various combinations thereof.

The differing angular positions can be located at the perimeter of the waveguide body and/or at one or more internal locations of the waveguide body. In having differing angular positions relative to the waveguide body, the light sources can be non-collinear. In some embodiments, the waveguide body has a polygonal shape, and the light sources have angular positions along two or more differing edges of the polygon. For example, the waveguide can be triangular, rectangular, hexagonal or octagonal, wherein banks of LEDs are positioned along two or more sides of the waveguide. In some embodiments, banks of LEDs are positioned on adjacent edges or sides of a polygonal waveguide. Banks of LEDs may also be along sides in facing opposition.

FIGS. 4A-4C illustrate luminaires comprising a polygonal waveguide body and light sources having differing angular positions relative to the waveguide body according to some embodiments. In the embodiment of FIG. 4A, LED banks 42 are arranged at differing sides of a triangular waveguide body 41. FIGS. 4B and 4C illustrate rectangular 43 and octagonal 44 waveguide bodies, respectively, having LED banks 42 arranged at differing sides. In some embodiments, the luminaire is oriented such that LED banks 42 are adjacent to wall(s) and/or ceiling(s) for directing the light distribution of the luminaire into a room or other environment. FIGS. 4A-4C illustrate various wall and/or ceiling configurations relative to orientation of the luminaire 40. As described herein, optics external to the waveguide can be employed to further alter illuminance distribution patterns of the luminaire in conjunction with light sources having differing angular positions. In the embodiments of FIGS. 4A-4B, optional reflectors 45 may be used to provide a hybrid luminaire construction.

LEDs or banks of LEDs can also exhibit differing angular positions at one or more internal locations of the waveguide body. In some embodiments, LEDs or banks of LEDs are placed in troughs having differing angular positions at internal locations of the waveguide body. The troughs can include internal coupling cavities for the LEDs.

FIG. 5A illustrates troughs 47 and associated LED banks 48 having different angular positions relative to the waveguide body 46 according to some embodiments. In the embodiment of FIG. 5A, the troughs 47 and LED banks 48 are parallel to two sides of the waveguide body 46 and normal to the remaining two sides. Other angular arrangements of the troughs relative to the waveguide body are contemplated. Moreover, internal coupling cavities can have differing positions at internal locations of the waveguide body as illustrated in FIG. 5B. The internal coupling cavities 49 can have dimensions for a single LED or banks of LEDs. The embodiment of FIG. 5B also includes an optional optic 45 external to the waveguide body 46 for further altering illuminance distribution patterns. Internal positioning of LEDs in conjunction with perimeter positioning of LEDs is also contemplated for altering illuminance distribution patterns of luminaires described herein.

In some embodiments, one or more banks of LEDs are shared between edges of differing waveguides. Waveguides, for example, are arranged in a lateral format, wherein bank(s) of LEDs can be shared between adjacent edges of the waveguides. The laterally arranged waveguides may further comprise banks of LEDs that are not shared. These unshared banks can be arranged at perimeter locations and/or internal locations of the waveguide body. For embodiments described herein, an LED bank can include a single LED or multiple LEDs.

The waveguide can also exhibit curved surfaces and can have a circular or elliptical shape, wherein banks of LEDs have differing radial angular positions along the curvature. In some embodiments, radial positioning of the LED banks can be symmetrical or asymmetrical. Further, LED banks can have differing radial angular positioning along a portion of a curvature or over the entire curvature.

Referring to the embodiment of FIG. 6 , a luminaire 10, in one aspect, comprises a waveguide 11 including a circular waveguide body 12 and a light extraction component 13 on a surface of the waveguide body 12. Light sources 14 have differing radial angular positioning along the waveguide body perimeter for steering an azimuthal component of illuminance distribution patterns of the luminaire in conjunction with the light extraction component 13. The waveguide 11 and light sources 14 are positioned within a frame 15, which can be reflective.

Turning now to specific components, the waveguide body 12 can be formed of any suitable waveguide material including acrylic, silicone, polycarbonate, glass and/or other suitable optically transmissive materials operable to support total internal reflection (TIR). Moreover, the waveguide body 12 can have any desired thickness. In some embodiments, for example, the waveguide body 12 has a thickness of 1 mm to 10 cm. Waveguide body thickness can be selected according to several considerations including, but not limited to, waveguide size and associated mechanical requirements, body material and/or desired geometry. The waveguide body can have any geometry consistent with steering an azimuthal component of illuminance distribution patterns of the luminaire in conjunction with spacing of the light sources along the waveguide perimeter. In the embodiment of FIG. 6 , the waveguide body 12 has a circular geometry. However, in other embodiments, the waveguide body can exhibit an elliptical or polygonal geometry including, but not limited to, square, rectangular, pentagonal or hexagonal.

The waveguide 11 includes a light extraction component 13 on or along one or more surfaces of the waveguide body 12. In other embodiments, the light extraction component can be within the waveguide body. In some embodiments, the light extraction component resides on one or both faces of the waveguide body. The light extraction component can comprise a single light extraction element or a plurality of individual light extraction elements. The size, shape and/or density of individual light extraction elements can be uniform or vary across one or more surfaces of the waveguide body in a regular or irregular fashion to produce desired azimuthal steering in conjunction with spacing of the light sources. Light extraction elements can comprise indents, depressions, facets or holes extending into the waveguide, or bumps, facets or steps rising above the waveguide surface, or a combination of both bumps and depressions. As described further herein, light extraction elements can be part of the waveguide body or coupled to surfaces of the waveguide body. In some embodiments, individual light extraction elements have a symmetrical shape or geometry. For example, individual light extraction elements can have a hemispherical profile or polygonal profile.

Another geometry which is particularly useful for a range of lighting applications includes a roughly “bullet shaped” profile as illustrated in FIGS. 7A-7C, consisting of a truncated curved surface 21 such as a truncated hemisphere with an adjacent cylindrical or conical base 22. This particular geometry provides a high degree of directionality as well as a range of possible illuminance distributions that may be realized by changing the height at which the curved surface is truncated. The height B of the hemispherical portion 21 affects the distribution of the light illumination of the waveguide 11 while the height C of the base 22 affects the percentage of light emitted downwardly relative to upward emitted light. With reference to FIG. 7B, the light extraction element 20, in one embodiment, can have dimensions listed in Table I.

TABLE I Light Extraction Element Dimensions A 0.025 mm B 0.415 mm C 0.085 mm D 1.0 mm E 0.050 mm F 0.510 mm radius of curvature G 89 degrees

Additional embodiments of light extraction elements 30 are illustrated in FIGS. 8A, 8B, 9A, and 9B. Each extraction feature 30 includes a body 31 having a curved shape that extends between an aperture 32 adjacent a surface of the waveguide body 12 and a base 33 opposite the aperture 32. The aperture 32 and the base 33 may be parallel or disposed at an angle relative to one another, as may be desired for a specialized asymmetric distribution. The body 31 may include planar surfaces, curved surfaces, planar surfaces approximating one or more curved surfaces, or a combination thereof. The cross sectional outer profile of the body 31 may be symmetric in nature (e.g., as in the case of a hemisphere) or asymmetric (e.g., as in the case of an ellipse or other combination of shapes when viewed from above or below). The body 31 may include a first portion 34 adjacent the aperture 32 and a second portion 35 adjacent the base 33. In some embodiments, the first portion 34 may be designed to redirect incident light downward through TIR. In some embodiments, shape of the extraction feature 30 may be determined by iteratively plotting the points defining an outer surface of the shape using a differential or quasi-differential equation.

With reference to FIG. 10 , the plurality of light extraction elements 51 of the light extraction component 50 can be arranged in an array, wherein the light extraction elements 51 exhibit regular or irregular spacing. In the embodiment of FIG. 10 , the light extraction elements 51 are positioned in a hexagonal array and are disposed on a substrate 52, which may be a planar member, such as a film, a plate, a block of material, or the like.

Referring to FIG. 11 , another example embodiment of an extraction film 60 includes a base 61 and undercut light extraction elements 62 disposed on the base 61. In this embodiment, the light extraction elements 62 form a series of elongate parallel protrusions 63 extending from the base 61. The elongate parallel protrusions 63 of the light extraction elements 62 seen in the embodiment of FIG. 11 may have a hemispherical cross section shape. A top portion 64 of the light extraction elements 62 may have a generally flattened surface 65 to provide a truncated hemispherical shape of the light extraction elements 62 extending from the base 61.

FIGS. 12 and 13 illustrate an example embodiment of an extraction film 70 in which light extraction elements 71 are disposed in a regular pattern atop a surface 72 of the base 73. In this illustrated example, the extraction film 70 comprises an array 74 of regularly-spaced light extraction elements 71, although it should be noted that the light extraction elements may be irregularly spaced or some may be regularly spaced and others irregularly spaced, etc. Further, the geometry and size of the light extraction elements 71 may vary across the film 70 in either a regular or irregular fashion. In this example, the optically transmissive film 70 may be formed with the light extraction elements 71 disposed in a hexagonal array 74 on the top surface 72 of the base 73. The undercut light extraction elements 71 are of substantially the same size and have substantially the same shape within the same extraction film member 70 in this embodiment. The undercut light extraction elements 71 arranged in the hexagonal array 74, in this example, have a truncated hemispherical shape. The light extraction elements 71 may have other shape(s) necessary to produce a desired light distribution. The light extraction elements 71 may be formed using one of a variety of techniques typically applied to the formation of micro-optical films, including gray-scale lithography, micro-replication, injection/compression molding, reactive ion etching, or chemical embossing during production of the optically transmissive film 70.

As seen in the embodiment of FIGS. 12 and 13 , the base 73 has a constant height H1 or thickness. In alternative embodiments, however, the thickness H1 of the base 73 may vary at different points along the base. Further, it may be desirable to fabricate varying degrees of roughness, or specific optical features, such as a second set or array of geometrical light extraction elements on the back surface 76 of the film 70 (FIG. 13 ) in order to further provide control over the azimuthal steering and illuminance distributions. Still further, the thickness H1 may be essentially zero (e.g., in cases where the light extraction elements 71 are fabricated directly on the waveguide surface. According to one embodiment, the thickness H1 of the base 73 is about 1 μm to about 5 mm or more, and more preferably is between 250 μm and about 3 mm and most preferably is equal to about 500 μm. Further, as seen in the illustrated embodiment of FIGS. 8A, 8B, 9A, and 9B, each of the truncated light extraction elements 71 of the extraction film 70 may have a height H2 (FIG. 13 ) extending from the base 73 that is substantially the same for each light extraction element. In alternative arrangements, the height H2 of the individual light extraction elements 71 may selectively vary within the same extraction film 70. In some embodiments, the extraction film 70 may be laminated or otherwise affixed to a surface of the waveguide body 12 such that the height H2 (FIG. 13 ) of the undercut light extraction elements 71 may be selectively varied to produce a wide range of illuminance distributions according to user preference.

The light extraction elements 71 extend from the top surface 72 of the base 73 to a generally flat surface 77 such that the curved shape of the light extraction member 71 is truncated by the flat surface. In this example, the truncated hemispherical light extraction elements 71 have a uniform rounded side surface 78, FIG. 13 , which extends from the top surface 72 of the base 73 to the generally flat surface 77 of the light extraction element 71. As such, with the light extraction elements 71 having a uniform rounded side surface 78, each light extraction element 71 has a cross section dimension that is largest proximal the base 73 and the cross sectional dimension becomes smaller distal from the base as the rounded side surface 78 extends from the base towards the flat portion 77. The hemispherical light extraction elements 71 may have a radius R at a preselected length that is truncated by the flat surface 77 to a preselected height H2. In one example, the hemispherical shaped light extraction elements 71 may have a 600 μm radius that is truncated to a height that may range, for example, between 100-590 μm. Of course, other radial lengths and truncated heights may selectively be employed. Still further, the minimum distances between adjacent light extraction elements 71 may selectively depend on the radius R of the light extraction element 71 and the limitations of the film fabrication method employed, with an example minimum distance being twice the radius (2×R) or greater. In other examples, values less than twice the radius (2×R) may be used where overlapping of the extraction elements 71 is desired for optical reasons (e.g., to improve extraction efficiency).

In the embodiment of FIG. 13 , the distances dx between the center points C of adjacent extraction elements 71 may be consistent throughout the array. The center-to-center spacing dx of the protruding light extraction elements 71 may selectively have a value of about twice the radius (2×R) in regions where a high level of extraction (and hence a luminance approaching the maximum possible light output for that region) is desired with the bases of the extraction elements 71 just in contact. In regions where reduced luminance are desired, values greater than twice the radius (2×R) can be used.

In some embodiments, the extraction elements 71 may be disposed on the waveguide body 12 without a base 73 or substrate. For example, the extraction elements 71 may be fabricated directly on surfaces of the waveguide body 12 by means of an intermediate patterning layer as described in U.S. Pat. No. 8,564,004, issued Oct. 22, 2013, entitled “Complex Primary Optics with Intermediate Elements” by Tarsa et al., incorporated by reference herein. Using this method of manufacture, the extraction elements 71 are optically joined to the waveguide body 12 without the need for the base 73. The patterning layer may be used with any method such as molding, injection molding, compression molding, dispensing, stencil printing, three-dimensional printing, photolithography, deposition, or the like. Specifically, the patterning layer is formed on surface(s) of the waveguide body 12 and includes holes or openings where the waveguide body 12 is exposed. The openings of the patterning layer correspond to locations where the extraction elements 71 are to be formed on the waveguide body 12. In some embodiments, a mold is then placed over the patterning layer and surface(s) of the waveguide body 12. The mold includes voids that are aligned with the openings of the patterning layer to define cavities. The cavities are filled with the material of the extraction elements 71. In other embodiments, the material of the extraction elements 71 is applied to the openings of the patterning layer prior to placement of the mold on the patterning layer. In either case, the material of the extraction feature is then at least partially cured and the mold is removed. The material of the patterning layer may comprise polyvinyl alcohol, a poly(methyl methacrylate) (PMMA) one or more photoresist materials, or other suitable materials. The patterning layer may be removed by a water rinse, heat, vaporization, machining, developers and solvents, chemical etching/solvent, plasma etching, or any method that does not interfere with the material of the waveguide body 12 and/or extraction elements 71. Alternatively, the waveguide body 12, the extraction elements 71, and/or the base 73 may be bonded to one another through one or more supplemental layers such as an adhesive layer or pressure-sensitive adhesive film.

FIGS. 14-16 illustrate alternative shaped light extraction elements. The light extraction elements in FIGS. 14-16 have prismatic shapes providing for alternative undercut geometries for light extraction. In particular, a penta prism shape 90 is shown in FIG. 14 , a dove prism shape 92 is shown in Figure and a porro prism shape 94 is shown in FIG. 16 . The prismatic shaped light extraction elements may be formed on the top surface 72 of the base 73 in alternative embodiments of the extraction film. The prismatic shaped light extraction elements may also be included with the truncated hemispherical light extraction elements 71 on the top surface 72 of the base 73 of the extraction film 70. For example a hexagonal array 74, FIGS. 12 and 13 , of light extraction elements 71 disposed on the base 73 of the light extraction member 71 may have both truncated hemispherical and prismatic shaped light extraction elements arranged in the array. Various arrangements and combinations of truncated curved and prismatic shaped light extraction elements may be selectively employed.

Light extraction elements may be of the same material as the base or substrate and/or the waveguide body, or the materials of the light extraction elements, the base, and/or the waveguide body may be different. In any event, the material(s) of the light extraction elements, the base and/or the waveguide body, preferably comprise optical grade materials that exhibit TIR characteristics including, but not limited to, one or more of acrylic, air, polycarbonate, molded silicone, glass, and/or cyclic olefin copolymers, and combinations thereof, possibly in a layered arrangement, to achieve a desired effect and/or appearance.

Referring again to FIG. 6 , the light sources 14 have differing radial angular positions along the waveguide body perimeter for steering an azimuthal component of illuminance distribution patterns of the luminaire in conjunction with the light extraction component 13. Any number of light sources can be spaced along the waveguide body perimeter. Number of light sources can be chosen according to several considerations including, but not limited to, geometry of the waveguide body, geometry of the array of light extraction elements and/or degrees of freedom for azimuthal steering.

Any light sources not inconsistent with the objectives of the present invention can be employed. Fluorescent and/or LED light sources, for example, can be used in the luminaire construction. LED light sources may comprise packaged LED chip(s) or unpackaged LED chip(s). LED elements or modules can use LEDs of the same or different types and/or configurations. The LEDs can comprise single or multiple phosphor-converted white and/or color LEDs, and/or bare LED chip(s) mounted separately or together on a single substrate or package that comprises, for example, at least one phosphor-coated LED chip either alone or in combination with at least one color LED chip, such as a green LED, a yellow LED, a red LED, etc. The LED module can comprise phosphor-converted white or color LED chips and/or bare LED chips of the same or different colors mounted directly on a printed circuit board (e.g., chip on board) and/or packaged phosphor-converted white or color LEDs mounted on the printed circuit board, such as a metal core printed circuit board or FR4 board. In some embodiments, the LEDs can be mounted directly to a heat sink or another type of board or substrate. Depending on the embodiment, the luminaire can employ LED arrangements or lighting arrangements using remote phosphor technology as would be understood by one of ordinary skill in the art, and examples of remote phosphor technology are described in U.S. Pat. No. 7,614,759, hereby incorporated by reference.

In those cases where a soft white illumination with improved color rendering is to be produced, each LED element or module or a plurality of such elements or modules may include one or more blue shifted yellow LEDs and one or more red or red/orange LEDs as described in U.S. Pat. No. 7,213,940, hereby incorporated by reference. The LEDs may be disposed in different configurations and/or layouts as desired. Different color temperatures and appearances could be produced using other LED combinations of single and/or multiple LED chips packaged into discrete packages and/or directly mounted to a printed circuit board as a chip-on board arrangement. In one embodiment, the light sources can comprise any LED, for example, an XP-Q LED incorporating TrueWhite® LED technology or as disclosed in U.S. patent application Ser. No. 13/649,067, filed Oct. 10, 2012, now U.S. Pat. No. 9,818,919, entitled “LED Package with Multiple Element Light Source and Encapsulant Having Planar Surfaces” by Lowes et al., the disclosure of which is hereby incorporated by reference herein. In another embodiment, the light sources can comprise XQ-E LEDs.

Any of the embodiments disclosed herein incorporating LED light sources may include power or driver circuitry having a buck regulator, a boost regulator, a buck-boost regulator, a fly-back converter, a SEPIC power supply or the like and/or multiple stage power converter employing the like, and may comprise a driver circuit as disclosed in U.S. patent application Ser. No. 14/291,829, filed May 30, 2014, now U.S. Pat. No. 9,791,110, entitled “High Efficiency Driver Circuit with Fast Response” by Hu et al. or U.S. patent application Ser. No. 14/292,001, filed May 30, 2014, now U.S. Pat. No. 9,303,823, entitled “SEPIC Driver Circuit with Low Input Current Ripple” by Hu et al., incorporated by reference herein. The circuit may further be used with light control circuitry that controls color temperature of any of the embodiments disclosed herein, such as disclosed in U.S. patent application Ser. No. 14/292,286, filed May 30, 2014, now U.S. Pat. No. 10,278,250, entitled “Lighting Fixture Providing Variable CCT” by Pope et al., incorporated by reference herein.

In some embodiments, each LED element or module may comprise one or more LEDs disposed within a coupling cavity with an air gap being disposed between the LED element or module and a light input surface. In any of the embodiments disclosed herein each of the LED element(s) or module(s) can have different or the same light distribution, although each may have a directional emission distribution (e.g., a side emitting distribution), as necessary for coupling with the waveguide.

In the embodiment of FIG. 6 , the light sources 14 are groupings of LEDs 16. The light sources 14 have differing radial angular positioning or spacing along the perimeter of the waveguide body 12 for steering an azimuthal component of illuminance distribution patterns of the luminaire in conjunction with the light extraction component 13. Generally, the light sources 14 can have any spacing along the perimeter of the waveguide body consistent with steering azimuthal components. Depending on the desired illuminance distribution pattern, the light sources can have equal or unequal spacing along the waveguide body perimeter. As described herein, the light extraction elements 13 can be arranged in arrays of various geometry. In the embodiment of FIG. 6 , for example, the light extraction elements 13 are disposed in a hexagonal array. Spacing of the light sources, in some embodiments, matches the polygonal geometry of the array of light extraction elements 13.

FIG. 17 illustrates one embodiment wherein spacing of the light sources matches the polygonal geometry of the array of light extraction elements. As illustrated in FIG. 17 , the light extraction elements 121 of the luminaire 120 are arranged in a hexagonal array 122. Similarly, the light sources 123 are spaced in a hexagonal format along the perimeter of the waveguide body 124. An azimuthal component of illuminance distribution patterns of the luminaire 120 can be steered by selectively lighting one or more of the light sources 123.

The illuminance distribution patterns of FIG. 18 illustrate such azimuthal steering. The number of each illuminance distribution pattern in FIG. 18 corresponds to the light source in FIG. 17 selectively lit to produce the distribution pattern. Alternatively, spacing of the light sources does not match the polygonal geometry of the array of light extraction elements.

FIG. 19 illustrates mismatch between the polygonal geometry of the array of light extraction elements and spacing of the light sources. The light extraction elements 121 of FIG. 19 are arranged in a hexagonal array 122 with the light sources 123 spaced in a pentagonal format along the perimeter of the waveguide body 124. This mismatch in geometry produces illuminance distribution patterns different than embodiments wherein the geometries are matched and illustrates the interdependence of light source spacing and light extraction component design for azimuthal steering.

FIG. 20 illustrates illuminance distribution patterns of the luminaire 120 of FIG. 19 when light sources are selectively lit. The number of each illuminance distribution pattern in FIG. 20 corresponds to the light source in FIG. 19 selectively lit to produce the distribution pattern. Steering azimuthal components as described herein permits dynamic alteration of illuminance distribution patterns.

Selectively lighting one or more light sources along the waveguide body perimeter resulting in azimuthal steering can be controlled by a computer or other programmable device. Selective lighting strategies and/or patterns for generating various azimuthal illuminance distributions can be stored on and executed by the computer or programmable device in conjunction with driver(s), current controller(s) and/or associated circuitry. Additionally, the computer or programmable device can allow a user to select lighting pattern(s), thereby initiating changes in illuminance distribution patterns of the luminaire. Changes in illuminance distribution patterns can also be conducted with reference to color temperature and color rendering aspects of the luminaire. In embodiments wherein LEDs are employed as light sources, luminaire color temperature can be altered in conjunction with the illuminance distribution patterns to provide real-time adjustments in response to changes in the lighting environment.

II. Waveguides with Dynamic Light Extraction Elements

In another aspect, a luminaire described herein comprises a waveguide body and light extraction component on and/or in the waveguide body, wherein the light extraction component includes one or more reversibly moveable surfaces for altering illuminance distribution patterns of the luminaire in response to one or more forces applied to the light extraction component.

As detailed further herein, forces can be applied mechanically, electrically and/or magnetically to reversibly moveable surfaces of the light extraction component by a force application assembly of the luminaire. In some embodiments, the reversibly moveable surfaces can form individual light extraction elements of the light extraction component. In such embodiments, the reversibly moveable surfaces are reversibly deflectable, expandable, contractible or combinations thereof. For example, the reversibly moveable surfaces can be deflected or expanded to form light extraction elements having shapes, profile and/or features of any of the light extraction elements described in Section I hereinabove. In some embodiments, reversibly moveable surfaces can be deflected or expanded to form light extraction elements of hemispherical profile. Height of the hemispherical profile can vary according to the amount of force applied to the reversibly moveable surfaces. In additional embodiments, the reversibly moveable surfaces can be deflected or expanded to provide light extraction elements having shapes and/or features illustrated in FIGS. 7A-16 herein. Alternatively, the reversibly moveable surfaces can be deflected to provide light extraction elements having concave profile, such as depressions or indents.

In some embodiments, a membrane is provided on one or more surfaces of the waveguide, wherein the membrane comprises an array of reversibly moveable surfaces. When deflected, expanded or contracted, the reversibly moveable surfaces form an array of light extraction elements. With reference to FIG. 10 , for example, reversibly moveable surfaces of the membrane 52 can form an array of light extraction elements 51 when deflected or expanded by application of one or more forces by a force application assembly of the luminaire. When the forces are removed, the surfaces return to an unraised or planar configuration, thereby smoothing the surface of the membrane 52.

Similarly, the reversibly moveable surfaces of the membrane can form light extraction elements 62 in a series of elongate parallel protrusions 63 as illustrated in FIG. 11 when deflected or expanded by the force application assembly. In further embodiments, the membrane is deflected or expanded as a monolithic piece, thereby providing a single light extraction element over the waveguide. For example, the membrane can be expanded to provide a single convex or domed light extraction element spanning the waveguide. Alternatively, the membrane can be deflected inwardly to provide a single concave light extraction element spanning the waveguide.

Forces can be applied to the reversibly moveable surfaces mechanically, electrically and/or magnetically. In some embodiments, the force application assembly comprises one or more channels and/or cavities for applying positive or negative fluid pressure to the reversibly moveable surface(s) of individual light extraction elements.

FIG. 21 illustrates one embodiment of a luminaire comprising a waveguide and light extraction component including one or more reversibly moveable surfaces for altering illuminance distribution patterns of the luminaire in response to application of positive or negative fluid pressure. As illustrated in the exploded view of FIG. 21 , the luminaire 160 comprises a waveguide body 161 having a plurality of fluid channels 162 formed thereon and light sources 170 positioned along the perimeter of the waveguide body 161. The waveguide body 161 can be formed of any optically transmissive material supporting TIR, including the waveguide materials described in Section I above.

A plate 163 having an array of cavities 164 is positioned over the face of the waveguide body 161, wherein the array of cavities 164 is in communication with the fluid channels 162. The fluid channels 162 and cavities 164 can have any arrangement/spacing on the waveguide body 161. For example, the cavities 164 can be arranged in arrays of various format, including polygonal and other arrays discussed in Section I above. In some embodiments, the cavities 164 are arranged in a hexagonal array on the waveguide body 161.

The plate 163 can be formed of any material not inconsistent with the objectives of the present invention. In some embodiments, the plate 163 is formed of an optically transmissive polymeric material. The plate 163, in one embodiment, is formed of the same material as the waveguide body 161. In other embodiments, the plate 163 is formed of a different material than the waveguide body 161. In such embodiments, the plate 163 and waveguide body 161 can be index matched or index mismatched. The plate 163 is covered with a flexible membrane 165. When covering the plate 163, the flexible membrane encloses the cavities 164.

FIG. 22 illustrates a cross-sectional view of the luminaire 160, wherein the cavities 164 are enclosed by the flexible membrane 165. FIG. 22 also illustrates the cavities 164 being in communication with the fluid channels 162. The flexible membrane 165 can be formed of any optically transmissive material not inconsistent with the objectives of the present invention. In some embodiments, the membrane 165 is formed of a polymeric material, such as one or more elastomers or thermoplastics. Material of the membrane 165 can have an index of refraction matching the waveguide body 161 and/or fluid disposed in the cavities 164 and channels 162. In other embodiments, material of the membrane is not index matched to the waveguide body 161 and/or fluid in the channels and cavities. Thickness of the membrane 165 can be selected according to several considerations including, but not limited to, membrane material, mechanical demands of the luminaire environment and flexibility required to reversibly form extraction elements of the desired profile and/or geometry in response to force(s) applied by the force application assembly. In some embodiments, membrane thickness is in the range of 0.5-10 mm. The membrane 165 can have a uniform thickness. Alternatively, thickness can vary between one or more regions of the membrane 165. For example, membrane thickness over individual cavities 164 can differ from membrane thickness in regions where the cavities 164 are absent. Variations in membrane thickness can enhance flexibility of the reversibly moveable surfaces without sacrificing mechanical stability of the membrane.

The membrane 165 can be coupled to the waveguide body 161 and/or plate 163 defining the array of cavities 164. In some embodiments, the membrane 165 can be bonded directly to the waveguide body 161 (e.g., through chemical or thermal bonding, or a combination of the two). Additionally, adhesive bonding and non-adhesive bonding may be employed to join the optical surfaces. The present disclosure also contemplates use of bonding processes that are adhesive-free to bond two structures permanently, preferably using heat and pressure. Other non-adhesive bonding processes may be alternatively or additionally used. Such processes can employ layers made of materials that can be bonded using light or other electromagnetic radiation, such as UV-curable resins, or layers that are secured together by a bonding agent that does not use adhesives, bonding layers using mechanical motion (e.g., ultrasonic vibration welding), heat welding (e.g., hot gas welding, hot plate welding, laser welding), induction welding, encapsulating materials in one layer with materials of another layer, chemically combining materials at an interface between layers, solvent welding (e.g., acetone, cyclohexane, 1,2-dichloroethane, methyl ethyl ketone, tetrahydrofuran), microscopically and/or macroscopically physically interspersing particles of one layer in another layer, providing a friction-fit, interference-fit, and/or suction fit between layers, securing layers together using one or more mechanical fasteners (e.g., staples, brads, rivets), or the like. Alternatively, the waveguide body 161 and membrane 165 may be bonded through one or more intermediate layers (such as an adhesive layer or pressure-sensitive adhesive film).

Fluid can be disposed in the fluid channels 162 and associated cavities 164 in conjunction with a pump or other apparatus to complete the force application assembly of the luminaire 160. Fluid of various optical properties can be employed. The fluid, in some embodiments, is optically transparent and has a refractive index matching or substantially matching the refractive index of the waveguide body 161. Alternatively, fluid index of refraction can be greater than or less than the index of refraction of the waveguide body 161. Further, the fluid may contain various additives such as scattering material, phosphors, dyes, upconverters and/or downconverters. The fluid, for example, can be selected from various oils including, but not limited to, immersion oils, aliphatic hydrocarbons, glycerin, mineral oil or mixtures thereof. In other embodiments, the fluid may be water or an aqueous-based mixture. Further, the fluid may be a gas such as air, nitrogen, argon or carbon dioxide.

One or more pumps or similar apparatus can be employed to manage the fluid in the channels 162 and cavities 164. In some embodiments, a pressure pump, syringe pump, peristaltic pump, electro-osmotic pump or piezoelectric pump can be coupled to the channels 162 of the waveguide body 161 by pipes or tubing.

FIG. 23 illustrates the assembled luminaire 160 with the pump 166 for applying pressure to the fluid in the channels 162 and cavities 164. The pump 166 in conjunction with the fluid channels 162, cavities 164 and fluid therein generally form the force application assembly of the luminaire 160. In some embodiments, the pump 166 applies a positive fluid pressure to the membrane 165 through the fluid channels 162 and cavities 164.

Application of the positive fluid pressure locally expands the membrane 165 over the cavity 164 to form a light extraction element 168 of convex profile as illustrated in FIG. 24B. Height or radius of the convex light extraction element 168 can be proportional to the amount of positive pressure applied. Cessation of the positive fluid pressure returns the membrane 165 to a relaxed state as illustrated in FIG. 24A. A negative fluid pressure can also be applied to the membrane 165. In such embodiments, the negative fluid pressure locally draws the membrane 165 inwardly toward the cavity 164 to form a light extraction element 169 having a concave or indented profile as illustrated in FIG. 24C. Depth or radius of the concave light extraction element 169 can be proportional to the amount of negative pressure applied. Cessation of the negative pressure returns the membrane 165 to the relaxed state of FIG. 24A.

Light extraction elements formed by application of fluid pressure to reversible moveable surfaces of the membrane 165 can alter illuminance distribution patterns of the luminaire 160. In some embodiments, positive or negative fluid pressure is applied to each of the cavities 164 to provide an array of convex or concave light extraction elements as illustrated in FIGS. 25A and 25B respectively. Alternatively, differing pressures can be applied to selected areas of the membrane 165 to provide individual light extraction elements or predetermined groupings of light extraction elements of differing profile to alter illuminance distribution patterns of the luminaire 160. For example, a positive fluid pressure can be applied to a first grouping of cavities 164 to provide a first grouping of light extraction elements having convex profile. A negative pressure can also be applied to a second grouping of cavities 164 to provide a second group of light extraction elements having concave profile. Similarly, a first pressure can be applied to a first grouping of cavities 164 to provide a first grouping of light extraction elements of a first height. A second pressure can be applied to a second grouping of cavities 164 to provide a second grouping of light extraction elements having a second height different from the first height. The first and second pressures can be selected from positive pressures and negative pressures. Any number or combination of differing light extraction elements based on application of differing pressures is contemplated.

Referring once again to FIG. 21 , the luminaire 160, in some embodiments, does not employ plate 163 and associated cavities 164. For example, the fluid channels 162 and cavities 164 can be formed as part of the waveguide body 161 as illustrated in FIG. 26 . The outer surface 165′ of the waveguide can have thickness responsive to pressure changes applied by the pump 166 in conjunction with fluid in the channels 162 and cavities 164 as illustrated in FIGS. 27A-27C. Alternatively, cavities 164 and associated fluid channels 162 are formed on the waveguide body 161 and subsequently covered by a membrane 165. For example, the channels 162 and cavities 164 can be formed in the waveguide body 161 by one or more techniques such as embossing, molding, stamping, additive manufacturing or lithography. Once formed, a membrane 165 can be applied to the waveguide body 161 for covering the cavities 164.

In some embodiments, an array of extraction lenses are formed on the surface of the waveguide body, the lenses including cavities in communication with fluid flow channels as described herein. The lenses can be capped with a flexible membrane for alteration by fluid pressure applied to the membrane via the flow channels and cavities.

FIG. 28 illustrates extraction lenses according to some embodiments described herein. As illustrated in FIG. 28 , extraction lenses 233 are formed on the waveguide body 231. The extraction lenses 233 comprise cavities 234 in communication with fluid channels 232 of the waveguide body 231. Fluid channels 232′ extend into the extraction lens 233 permitting fluid to enter the cavity 234. The cavity 234 of each extraction lens is covered with a flexible membrane 235 for alteration by fluid pressure applied to the membrane 235 via the flow channels 232 and cavities 234.

Fluid channels and cavities of dynamic light extraction elements described herein can have any dimensions not inconsistent with the objectives of the present invention. In some embodiments, for example, the fluid channels and/or cavities have dimensions for managing microliters of fluid. In other embodiments, the fluid channels and/or cavities can accommodate milliliters of fluid.

To illustrate alterations in illuminance distribution patterns with varying extraction element profile, a luminaire having the construction illustrated in FIG. 6 was modeled. Simulations of illuminance distribution patterns were conducted with the luminaire employing hemispherical light extraction elements of differing height or radius. Simulations were conducted for luminaire embodiments employing a backside reflector as well as embodiments wherein a backside reflector was absent.

FIG. 29 illustrates changes in illuminance distribution patterns of the luminaire with changing radius of the hemispherical light extraction elements. The simulations of FIG. 29 were conducted without a backside reflector. FIG. 30 illustrates alterations to the illuminance distribution patterns of FIG. 29 when a specular backside reflector was added to the luminaire construction. In a similar manner, illuminance distribution patterns were simulated for light extraction elements having a concave profile.

FIG. 31 illustrates changes in illuminance distribution patterns of the luminaire with changing depth or radius of the concave light extraction elements. FIG. 32 illustrates alterations to the illuminance distribution patterns of FIG. 31 when a specular backside reflector was added to the luminaire construction.

In further embodiments, surfaces of light extraction elements can be reversibly deflected, expanded or contracted via pathways other than fluid pressure. In some embodiments, for example, the reversibly moveable surfaces comprise piezoelectric materials or electroactive polymers operable to move in response to an applied electric field. In such embodiments, the force application assembly of the luminaire can include electrodes and associated circuitry for application of electric field(s) to induce deflection and formation of light extraction elements of desired profile and/or geometry.

Polymeric materials having piezoelectric properties, in some embodiments, can be employed in the reversibly moveable surfaces of individual light extraction elements. Piezoelectric polymeric materials can include ferroelectric polymers such as polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), polyvinylidene fluoride-tetrafluoroethylene (PVDF-TFE). Moreover, polymeric composite materials exhibiting piezoelectric properties can be used in the reversibly moveable surfaces. Acrylics, polyolefins and/or polycarbonate, for example, can be doped with piezoelectric particles to provide surfaces responsive to an applied electric field. Piezoelectric particles can include titanate (BaTiO3) particles, bismuth telluride particles (BiTe), other inorganic particles or mixtures thereof. Other suitable electrically responsive materials can include dielectric elastomers including, but not limited to, acrylic and silicone elastomers. Conducting polymers such as polypyrrole, polyaniline, polythiophene and/or derivatives thereof may also be used in reversibly moveable surfaces responsive to an applied electric field or voltage.

Referring once again to FIG. 10 , each of the light extraction elements 51 can comprise an assembly of piezoelectric or electroactive polymer positioned between electrodes. Application of an electric field or voltage by the electrodes deflects or expands the piezoelectric or electroactive polymer to form the bump light extraction elements 51. Light extraction elements having shapes, profiles and/or features of any of the light extraction elements described in Section I herein may also be formed by electrode-electroactive polymer assemblies. In some embodiments, optically transparent electrode materials can be used, including optically transparent conducting oxides. Optically transparent conducting oxides can comprise indium tin oxide (ITO), gallium indium tin oxide (GITO), and zinc indium tin oxide (ZITO). Surfaces of light extraction elements can also be reversibly deflected, expanded or contracted via magnetic pathways. Surfaces of light extraction elements, for example, can include magnetic elements for response to an applied magnetic field.

As described herein, the force application assembly can provide one or more forces to the light extraction elements individually or in predetermined groupings to provide the desired illuminance distribution pattern of the luminaire. The force application assembly can be controlled by a computer or other programmable device. Force application strategies and/or patterns for generating various illuminance distributions with the light extraction elements can be stored on and executed by the computer or programmable device. For example, fluid pressures and valves for routing application of the fluid pressures to cavities of light extraction elements to be altered can be controlled by the computer. In piezoelectric or electroactive polymer embodiments, electrode assemblies can be independently controlled with appropriate circuitry for application of electric field to selected light extraction elements. Moreover, the computer or programmable device can allow a user to alter forces applied to light extraction elements, thereby initiating a change in illuminance distribution pattern of the luminaire. In being part of the luminaire construction, the force application assembly precludes adjustment via one or more means external to the device, such as by individually manually moving, adding or removing optical element(s) of the luminaire. Changes in illuminance distribution patterns can also be conducted with reference to color temperature and color rendering aspects of the luminaire. In embodiments wherein LEDs are employed as light sources, luminaire color temperature can be altered in conjunction with the illuminance distribution patterns to provide real-time adjustments in response to changes in the lighting environment.

Any of the embodiments disclosed herein may be used in a luminaire having one or more communication components forming a part of the light control circuitry, such as an RF antenna that senses RF energy. The communication components may be included, for example, to allow the luminaire to communicate with other luminaires and/or with an external wireless controller, such as disclosed in U.S. patent application Ser. No. 13/782,040, filed Mar. 1, 2013, now U.S. Pat. No. 8,975,827, entitled “Lighting Fixture for Distributed Control” or U.S. Provisional Application No. 61/932,058, filed Jan. 27, 2014, entitled “Enhanced Network Lighting,” the disclosures of which are incorporated by reference herein. More generally, the control circuitry can include at least one of a network component, an RF component, a control component, and one or more sensors. A sensor, such as a knob-shaped sensor, may provide an indication of ambient lighting levels and/or occupancy within the room or illuminated area. Other sensors are possible, and a sensor may be integrated into the light control architecture governing the force application assembly.

III. Hybrid Luminaires

In a further aspect, luminaires of hybrid construction are described, which include at least one waveguide body in conjunction with one or more conventional optics. In some embodiments, for example, a luminaire comprises at least one light source and a waveguide including a waveguide body and light extraction component(s) on and/or in the waveguide body. At least one optic external to the waveguide is arranged to receive at least a portion of light from the waveguide and/or a portion of light directly from the light source. The at least one external optic can be a reflector or lens.

Turning now to specific components, the waveguide body can be formed of any suitable material, including the waveguide materials listed in Section I herein. Moreover, the waveguide body can have any desired geometry or shape. In some embodiments, the waveguide body can be polygonal, circular or elliptical. Shape of the waveguide body may also combine polygonal elements with circular and/or elliptical elements. Further, the waveguide body may be planar, curved or combinations thereof. Shape and dimensions of the waveguide body can be selected according to several considerations including, but not limited to, waveguide material, overall luminaire design, luminaire application(s) and associated lighting requirements. The waveguide body, for example, can have shape and dimensions suitable for pendant, surface mount, wall mount and/or stand-alone luminaires.

The light extraction component of the waveguide can have any desired construction and/or design. Design of the light extraction component can be selected according to several considerations including, but not limited to, lighting requirements and applications of the luminaire, geometry/shape of the waveguide body and/or arrangement of the light sources of the luminaire. In some embodiments, the light extraction component has a construction or design described in Section I hereinabove. Light extraction elements, for example, can have shapes and/or features illustrated in FIGS. 7-16 herein. Alternatively, the light extraction component can incorporate the dynamic light extraction elements described in Section II hereinabove employing reversibly moveable surfaces.

Hybrid luminaires described herein can employ a variety of light sources including incandescent, fluorescent or LED. In some embodiments, for example, LEDs described in Section I hereinabove are employed in the luminaire construction. Type and number of light sources can be selected according to luminaire lighting and performance requirements, including lumen output, color temperature and color rendering. The light source(s) can have any desired arrangement relative to the waveguide. In some embodiments, light sources are arranged along the perimeter of the waveguide body. For example, the light sources can have spacing to permit azimuthal steering as described in Section I herein. Alternatively, one or more light sources may have a central arrangement, such as in a coupling cavity between adjacent waveguides.

The luminaire comprises at least one optic external to the waveguide, wherein the optic is arranged to receive at least a portion of light from the light extraction component and/or light directly from the luminaire light source(s). In some embodiments, the optic is arranged to receive all or substantially all of the light emitted from the waveguide by the light extraction component. The external optic can have any desired arrangement relative to the waveguide. In some embodiments, the external optic has a radial arrangement relative to the waveguide. In such embodiments, the external optic can surround or partially surround the waveguide. For example, in some embodiments, the waveguide and external optic are concentrically arranged. In other embodiments, the external optic can be arranged parallel to the waveguide.

External optic(s) of hybrid luminaires described herein can be reflective optics, refractive optics or various combinations thereof. Depending on the lighting application, suitable reflective optics can provide specular reflection or diffusion reflection. In some embodiments, reflective optics employ one or more curved surfaces, including concave and/or convex surfaces. Reflective surfaces may also incorporate a photoluminescent component, such as a phosphor or dye coating. A phosphor or dye coating may cover all or selected portion(s) of the reflective surface. In some embodiments, the light extraction component can be used to irradiate selected areas of the reflector via the dynamic extractors described in Section II and/or the azimuthal steering described in Section I herein. An external optic of the luminaire, in some embodiments, includes an array of sub-optical elements. The sub-optical elements can be in alignment with the array of light extraction elements. A refractive optic, for example, can comprise an array of lenses having alignment with the array of light extraction elements of the waveguide.

By receiving light from the light extraction component, the external optic is operable to redirect the light and alter illuminance distribution patterns of the luminaire. In some embodiments, the external optic can function as a collimator or otherwise narrow the light distribution received from the light extraction component. Depending on the type and arrangement of the external optic, a variety of illuminance distribution patterns can be produced. The variety of illuminance distribution patterns can be further increased when the luminaire construction incorporates azimuthal steering of Section I and/or dynamic light extractors of Section II.

FIG. 33 illustrates one embodiment of a luminaire comprising a waveguide and optic external to the waveguide. The waveguide and associated light sources can have architectures as illustrated in FIG. 6 . A parabolic specular reflector surrounds the waveguide and receives light from the light extraction component of the waveguide. In the embodiment of FIG. 33 , the parabolic specular reflector redirects the received light while narrowing the illuminance distribution pattern.

The ability to dynamically alter illuminance distributions enables luminaires described herein to find application in a variety of lighting environments. For example, luminaires can find application in office or retail lighting wherein the illuminance distribution is specifically tailored to direct light where needed and minimize light where it is not. In such applications, illuminance distribution patterns can be based on real-time sensing of occupancy, occupant position, time of day and/or window number and positioning. Color temperature can also be varied with the illuminance distribution to provide additional lighting enhancements and effects, such as in architectural or museum lighting. Luminaires described herein can also be used as skylight and/or window simulators designed to provide a sense of a naturally sunlit room wherein illuminance distribution changes in a manner consistent with changing sun position during the day. Luminaires described herein may also find application in dynamic street lighting permitting real-time adjustments to illuminance distributions to match various conditions including roadway occupancy, weather and ambient lighting conditions.

IV. Bonded Assemblies for Waveguides

As discussed in relation to FIG. 1 , light extraction elements can de-bond from the waveguide body in response to flexural loads and/or other stresses applied to the waveguide body. Careful investigation has revealed that de-bonding can be particularly severe when loads and/or stresses are applied at locations of the waveguide body where extraction elements are absent. For example, flexural loads applied to one or more edges of the waveguide body can initiate and propagate de-bonding of extraction elements. In many cases, de-bonding of an extraction element initiates along an edge of the extraction element proximate the edge of the extractor plate and proceeds in an inward direction.

FIGS. 34A and 34B illustrate one embodiment of initiation and progression of extraction element de-bonding, respectively. Initiation in FIG. 34A occurs along the arc closest to the edge of the extractor plate (EP) experiencing the flexural load. De-bonding and failure progresses across the extraction element as illustrated in FIG. 34B. Other de-bonding mechanisms of an extraction element are also possible. De-bonding may initiate at other edges of the extraction element and progress in directions parallel to and/or toward the extractor plate edge. In further embodiments, de-bonding may initiate in a central region of the extractor element and progress outward in one or more radial directions. De-bonding mechanism of an extractor element can be influenced by several considerations including, but not limited to, direction(s) of applied flexural load, extractor element geometry and bonding footprint of the extractor element with the waveguide body.

In view of de-bonding and other failure modes, a waveguide assembly described herein comprises a waveguide body and light extraction elements bonded to the waveguide body, wherein at least one reinforcement member is coupled to the waveguide assembly at one or more locations to reduce deflection of the waveguide assembly under an applied flexural load. Turning now to specific components, the waveguide body can be formed of any suitable waveguide material including acrylic, silicone, polycarbonate, glass and/or other suitable optically transmissive materials operable to support TIR. In some embodiments, for example, the waveguide body is formed of PMMA or a derivative thereof.

The waveguide material can be selected according to various considerations including the mechanical and/or chemical demands of the environment in which the waveguide body will operate. In some embodiments, more rigid materials may be selected to assist in reducing deflection in response to an applied flexural load. Moreover, the waveguide body can have any dimensions and shape not inconsistent with the objectives of the present invention. In some embodiments, the waveguide body has a thickness of 1 mm to 10 cm. The waveguide body thickness can be selected according to several considerations including, but not limited to, waveguide size and associated mechanical requirements, body material and/or desired geometry. In some embodiments, the waveguide body is provided thickness sufficient to assist in deflection reduction.

The waveguide body, in some embodiments, is generally planar or plate-like. A planar waveguide body can be polygonal, such as square, rectangular, hexagonal, etc. Alternatively, a planar waveguide body can be circular, elliptical or exhibit at least one curved edge or surface.

Light extraction elements are bonded to the waveguide body. Light extraction elements may be bonded to one or more surfaces of the waveguide body. For example, light extraction elements can be bonded to one or both faces of the waveguide body. The size, shape and/or density of individual light extraction elements can be uniform or vary across one or more surfaces of the waveguide body in a regular or irregular fashion to produce desired light distribution in conjunction with the light sources. Light extraction elements bonded to the waveguide body can have any desired shape. In some embodiments, light extraction elements can be protrusions, bumps, depressions or various combinations thereof. Light extraction elements have symmetrical shape or geometry. For example, individual light extraction elements can have a hemispherical profile or polygonal profile.

Returning to FIGS. 7A-7C, another geometry particularly useful for a range of lighting applications includes a roughly “bullet shaped” profile, consisting of a truncated curved surface 21, such as a truncated hemisphere with an adjacent cylindrical or conical base 22. If desired, a bonding feature 24 having a central planar portion 23 may be formed atop the truncated hemispherical portion 21. In some embodiments, the bonding feature 24 facilitates fabrication by enabling the bond between the extraction element 20 and the waveguide surfaces to be free of air pocket(s) that may otherwise form. Additional embodiments of light extraction elements 30 are illustrated in FIGS. 8A, 8B, 9A, and 9B.

As described above, FIGS. 14-16 illustrate alternative shaped light extraction elements. Various arrangements and combinations of truncated curved and prismatic shaped light extraction elements may be selectively employed.

As described herein, light extraction elements can be part of a light extractor plate. The light extraction elements, for example, can be arranged on a substrate or base. The substrate may be a planar member such as a film, a plate, a block of material or the like. Referring again to FIG. 11 , an example of an extractor plate 60 includes a base 61 and undercut light extraction elements 62 disposed on the base 61. FIGS. 12 and 13 illustrate another embodiment of an extractor plate 70 in which light extraction elements 71 are disposed in a regular pattern atop a surface 72 of the base 73.

FIG. 35 illustrates an extractor plate bonded to a waveguide body according to some embodiments described herein. As illustrated in FIG. 35 , the extraction elements 302 are associated with a substrate or base 301 of the extractor plate 300. The extractor plate 300 is bonded to a light emitting surface of the waveguide body 303 via the extraction elements 302. The light extraction elements 302 may be bonded to the waveguide body 303 either directly or with one or more intermediate layers using a variety of bonding methods including ultrasonic bonding, laser bonding, adhesive bonding, pressure-sensitive adhesive bonding, chemical welding, thermal bonding or combinations thereof. In some embodiments, multiple extractor plates 300 may be bonded to a light emitting surface of the waveguide body 303. For example, the desired number of extraction elements 302 may be divided over multiple extractor plates 300. Use of multiple extractor plates 300 can assist with inhibiting and/or arresting de-bonding mechanisms described herein.

FIG. 36 illustrates multiple extractor plates bonded to a light emitting surface of a waveguide body according to some embodiments. As illustrated in FIG. 36 , the extraction elements 312 are spread over several extractor plates 310(a)-(d). By lacking a common substrate or base 311, tensile and/or shear stresses experienced at one extractor plate, 310(a) for example, are not transmitted to extraction elements 312 of the remaining plates 310(b)-(d). Therefore, de-bonding and other failure modes can be localized and effectively managed across the entire waveguide assembly.

As described herein, extraction elements may alternatively be disposed on the waveguide body without a base or substrate. For example, the extraction elements may be fabricated directly on surfaces of the waveguide body by means of an intermediate patterning layer as described in U.S. Pat. No. 8,564,004, issued Oct. 22, 2013, entitled “Complex Primary Optics with Intermediate Elements” by Tarsa et al., incorporated by reference herein. Using this method of manufacture, the extraction elements are optically joined to the waveguide body without the need for the base. The patterning layer may be used with any method such as molding, injection molding, compression molding, dispensing, stencil printing, three-dimensional printing, photolithography, deposition, or the like. Specifically, the patterning layer is formed on surface(s) of the waveguide body and includes holes or openings where the waveguide body is exposed. The openings of the patterning layer correspond to locations where the extraction elements are to be formed on the waveguide body.

In some embodiments, a mold is then placed over the patterning layer and surface(s) of the waveguide body. The mold includes voids that are aligned with the openings of the patterning layer to define cavities. The cavities are filled with the material of the extraction elements. In other embodiments, the material of the extraction elements is applied to the openings of the patterning layer prior to placement of the mold on the patterning layer. In either case, the material of the extraction feature is then at least partially cured and the mold is removed. The material of the patterning layer may comprise polyvinyl alcohol, a PMMA, one or more photoresist materials, or other suitable materials. The patterning layer may be removed by a water rinse, heat, vaporization, machining, developers and solvents, chemical etching/solvent, plasma etching, or any method that does not interfere with the material of the waveguide body and/or extraction elements. In further embodiments, the extraction elements are fabricated independent of the waveguide body and subsequently picked and placed in the desired location of the waveguide body. Extraction elements of any size and shape can be independently fabricated and subsequently placed in an array or random position on the waveguide body.

Alternatively, the waveguide body, the extraction elements and/or the base may be bonded to one another through one or more supplemental layers such as an adhesive layer or pressure-sensitive adhesive film. Additional extraction element and extractor plate architectures are described in U.S. patent application Ser. No. 14/472,078 entitled “Waveguide Having Unidirectional Illuminance” by Tarsa et al., U.S. patent application Ser. No. 14/472,035, now U.S. Pat. No. 9,645,303, entitled “Luminaires Utilizing Edge Coupling” by Tarsa et al., and U.S. patent application Ser. No. 14/472,064, now U.S. Pat. No. 10,209,429, entitled “Luminaire with Selectable Luminous Intensity Pattern,” each of which is incorporated herein by reference in its entirety.

As described herein, at least one reinforcement element is coupled to the waveguide assembly at one or more locations to reduce deflection of the waveguide assembly under an applied flexural load. It is preferable that reinforcement elements do not materially alter the lighting characteristics and/or performance of the waveguide assembly. Reinforcement elements can be of any structure operable to reduce deflection of the waveguide assembly while under an applied flexural load.

In some embodiments, a reinforcement member comprises one or more bars or rods coupled to the waveguide assembly. A reinforcement bar can be of any length and shape. A reinforcement bar, for example, can be linear, curved or various combinations thereof. In some embodiments, a reinforcement bar has an accordion or zig-zag form. A reinforcement bar can also have a coiled or serpentine form or arrangement. Moreover, a reinforcement bar can have any cross-sectional profile. A reinforcement bar can have a polygonal, circular or elliptical cross-sectional profile, in some embodiments.

Additionally, the cross-sectional profile of a reinforcement bar can be tailored to minimize contact with the waveguide assembly while providing sufficient strength for reducing deflection of the waveguide assembly under an applied load. The reinforcement bar, for example, can be thinner at the base for minimizing contact with an optical surface, such as the waveguide body, and expand in the vertical dimension. In some embodiments, height of a reinforcement bar changes along length of the bar. A reinforcement bar can have increased height at locations of the waveguide assembly experiencing high tensile and/or shear stresses and decreased height at other locations. Reinforcement bars or rods can be independent of one another or can be connected in any manner including but not limited to, end to end, overlapping or stacked.

A reinforcement member can also be a frame. In some embodiments, a frame comprises two or more reinforcement members connected to one another. For example, two or more reinforcement bars or rods can be connected to form a frame. As detailed further herein, a frame can have any shape including polygonal, circular, elliptical or various combinations thereof. In some embodiments, frame shape generally matches the shape of the waveguide body or extractor plate.

A frame can be closed in that sides of the frame are connected to define a closed interior region of the frame. Alternatively, a frame can be open in that the sides of the frame do not define a closed interior region. Additionally, sides of a frame can be the same or substantially the same. In other embodiments, two or more sides of a frame can be different from one another in at least one property or design. Sides of a frame, for example, can be of different materials, shapes and/or dimensions. In some embodiments, one or more sides of a frame are polymeric material while other frame sides are metal or alloy, such as steel. Height and/or cross-sectional geometry of frame sides may also vary.

The construction and design of an individual side of a frame can be tailored according to the stress environment experienced by the side. Sides of a frame experiencing high shear and/or tensile stresses transmitted by the waveguide assembly can be fabricated from more rigid materials and/or have different cross-sectional profile in comparison to frame sides in a lower stress field. Moreover, construction and design of a frame side can also be dependent on the optical properties and performance of the waveguide assembly. Frame sides can be designed to minimize optical disruptions while providing sufficient resistance to deflection. In some embodiments, a single frame is used to enhance structural rigidity of the waveguide assembly. In other embodiments, multiple frames may be employed. Multiple frames, for example, may be coupled to the waveguide body at one or more locations.

In some embodiments, multiple frames are stacked upon one another. Multiple frames can also have concentric or eccentric orientation relative to one another. Additionally, several components of the waveguide assembly can have a frame coupled thereto. In some embodiments, a first frame is coupled to the waveguide body and a second frame is coupled to an extractor plate. In other embodiments, a frame is employed to couple components of the waveguide assembly. For example, a frame can exhibit a clamping arrangement for coupling the waveguide body and extractor plate together.

In further embodiments, a reinforcement member is an adhesive bonding one or more components of the waveguide assembly to increase rigidity of the assembly. As detailed further herein, an adhesive can be employed to bond one or more edges of an extractor plate to the waveguide body. An adhesive, for example, can be positioned on the base of an extractor plate outside the bonding region defined by the light extraction elements bonded to a light emitting surface of the waveguide body. The adhesive may be placed between one or more edges of the extractor plate and waveguide body. The adhesive can increase bonding between the extractor plate and waveguide body, thereby increasing resistance to de-bonding and other failure mechanisms.

Location(s) of the one or more reinforcement elements can be determined according to several factors including, but not limited to, the construction and arrangement of the light extraction elements, desired optical properties and lighting performance characteristics of the waveguide assembly and load transmission properties of the waveguide assembly. For example, one or more reinforcement members can be coupled to the waveguide assembly outside light emitting regions. Moreover, one or more reinforcement members can be placed at locations of the waveguide assembly where generation and/or transmission of tensile and/or shear stresses is the greatest. In some embodiments, light extraction elements define a light emission region and a reinforcement member is coupled to the waveguide assembly outside the light emission region.

One or more bars can be coupled to the waveguide body outside the light emission region. Alternatively, a frame can be coupled to the waveguide body outside the light emission region. In some embodiments, the frame can surround the light emission region defined by the light extraction elements.

FIG. 37A illustrates a cross-sectional view of a reinforcing frame surrounding a light emission region of a waveguide assembly according to some embodiments described herein. The cross-sectional view is taken along the A-A line of FIG. 37B. The light emission region 321 of the waveguide assembly 320 is defined by an extractor plate 322 bonded to the waveguide body 324 via extraction elements 323. The reinforcing frame 325 is coupled to the waveguide body 324 and surrounds the extractor plate 322.

FIG. 37B illustrates a top plan view of the reinforcing frame 325 coupled to the waveguide assembly 320. In being coupled to the waveguide body 324 outside the light emission region 321 defined by the extractor plate 322, the reinforcing frame 325 does not materially interfere with the optical properties and lighting performance of the waveguide assembly 320. The reinforcing frame 325 can be coupled to the waveguide body 324 by a variety of non-limiting mechanisms. In some embodiments, adhesive is used to couple the reinforcing frame 325 to the waveguide body 324.

In other embodiments, the reinforcing frame 325 is coupled to the waveguide body 324 by one or more mechanical fasteners. Any mechanical fastener not inconsistent with the objectives of the present invention may be employed. In some embodiments, a mechanical fastener comprises a screw or bolt assembly. In other embodiments, a mechanical fastener can include one or more clips. FIG. 37C illustrates a screw or bolt assembly 326 coupling the reinforcing frame 325 to the waveguide body 324 according to one embodiment.

As described herein, a plurality of reinforcing members can be coupled to the waveguide assembly to reduce deflection of the waveguide assembly under an applied flexural load. In the embodiment of FIG. 38 , for example, a first reinforcing frame 335 is coupled to the waveguide body 334 and a second reinforcing frame 336 is coupled to the extractor plate 332. In other embodiments, multiple frames can be coupled to the waveguide body. In some embodiments employing multiple frames, the frames can have a concentric arrangement or eccentric arrangement. Additionally, a single frame may couple to the waveguide body and extractor plate.

FIG. 39 illustrates an arrangement wherein a clamping frame 345 is coupled to the waveguide body 344 and extractor plate 342. As described herein a frame can couple to the waveguide body and/or extractor plate via adhesive and/or mechanical fastener(s). In some embodiments, the entire bottom surface of the frame engages the waveguide body directly or through an adhesive. Alternatively, coupling is accomplished through several discrete contact points between the frame and waveguide body. In some embodiments, the frame is coupled to the waveguide body at one or more vertices of the frame. In other embodiments, the frame is coupled to the waveguide body at one or more discrete points along side(s) of the frame. Coupling via discrete contact points minimizes contact between the frame and waveguide body. Minimization of this contact can preclude optical disruptions and losses precipitated by light propagating in the waveguide body interacting at interfaces of the frame and waveguide body.

In some embodiments, one or more spacers are positioned at coupling locations between the frame and waveguide body. The spacers lift the frame off the waveguide surface, thereby minimizing optical disruptions. Spacing the frame from the surface of the waveguide body can minimize or preclude undesirable optical coupling events and/or prevent scratching of the waveguide surface by the frame. Scratches in the waveguide surface can precipitate optical losses and undesirable alterations to the lighting distribution of the waveguide assembly. Spacers can also be employed with any reinforcement member, such as bars or rods described herein, to minimize surface contact between the reinforcement member and waveguide body. Spacers may additionally be used in a similar manner with reinforcement members coupled to an extractor plate.

In some embodiments, optical efficiency of the waveguide assembly is reduced less than 5 percent by the one or more reinforcement members. Reinforcement members can be formed of materials different than components of the waveguide assembly to which the reinforcement members are coupled. In some embodiments, a reinforcing bar, rod or frame is a metal or alloy, such as aluminum or steel, while the waveguide body and/or extractor plate comprises polymeric material. When the reinforcement member is formed of a different material than waveguide assembly component(s), various measures can be employed to address mismatches in coefficients of thermal expansion (CTE) between the reinforcement member and waveguide assembly component(s).

As described above, one or more spacers are positioned between the reinforcement member and waveguide body. The spacer can raise the reinforcement member above the surface of the waveguide body, thereby minimizing contact between the reinforcement member and waveguide body. The spacer can also be formed of a material bridging the CTE mismatch between the reinforcement member and waveguide body. Additionally, apertures of varying diameter can be used to address CTE mismatch between the reinforcing member and waveguide body.

FIG. 40 is a cross-sectional view of mechanical coupling of reinforcement elements to a waveguide body according to some embodiments. As provided in FIG. 40 , a screw or bolt assembly 351 couples the reinforcement elements 355 to the waveguide body 354. The screw or bolt assembly 351 comprises washers 352 in addition to the screw or bolt 353. The reinforcement elements 355 may be individual bars or frames. In some embodiments, the reinforcing elements 355 are sides of a clamping frame. In the embodiment of FIG. 40 , the reinforcing elements 355 are formed of structural steel or aluminum, and the waveguide body 354 is formed of PMMA. CTEs for these materials are provided in Table II.

TABLE II CTE (ppmPC) Material CTE PMMA 70 Aluminum 22 Structural Steel 13

This CTE mismatch can cause binding of the screw or bolt 353 in response to temperature fluctuations. This binding can deflect the reinforcement members 355 resulting in flexure and application of detrimental stresses to the waveguide body 354. To address this, apertures 356 in the reinforcement members 355 and waveguide body 354 are provided diameters permitting independent expansion and/or contraction movements between reinforcing members 355 and waveguide body 354. In the embodiment of FIG. 40 , apertures 356 of the reinforcement members 355 are larger in diameter than the aperture 357 in the waveguide body. However, other aperture diameter arrangements are possible depending on material systems employed and design of the coupling arrangement. In some embodiments, for example, aperture of the waveguide is larger than an aperture in one or more reinforcing members. Additionally, aperture shape may be varied between the reinforcing member(s) and waveguide body to address CTE differences. In some embodiments, problems with CTE mismatch are obviated by use of adhesive reinforcing member(s).

FIG. 41 illustrates application of an adhesive between an extractor plate and waveguide body according to some embodiments. In the embodiment of FIG. 41 , the extraction elements 361 of the extractor plate 362 define a bonding region 363 between the extractor plate 362 and waveguide body 364. An adhesive reinforcement member 365 is positioned outside the bonding region 363 to further couple the extractor plate 362 to the waveguide body 364. In the embodiment of FIG. 41 , the adhesive reinforcement member 365 is applied along one or more edges 366 of the extractor plate 362. The adhesive reinforcement element 365 can be a polymeric material having CTE matching or similar to the polymeric materials forming the waveguide body 364 and extractor plate 362. In some embodiments, an acrylic adhesive is employed for acrylic waveguide bodies and extractor plates.

As described herein, one or more reinforcement members coupled to the waveguide assembly can preclude de-bonding of the light extraction elements under the applied flexural load. In some embodiments, the applied flexural load is sufficient to de-bond light extraction elements in the absence of the reinforcement member(s). For example, the applied flexural load can be at least 20 pounds. In some embodiments, the applied flexural load is selected from Table III.

TABLE III Flexural Load Applied to Waveguide Assembly Flexural Load (lbs) > 30 > 60  30-150  40-120  50-100 60-90

For purposes of evaluating waveguide assemblies and associated reinforcement member(s) described herein, flexural loads are applied according to the three-point bend apparatus illustrated in FIG. 42 . The waveguide assembly 370 including any reinforcement members (not shown) is suspended between two linear supports (a) with the light emitting surface comprising bonded extraction elements facing down. Incremental weight (b) is added to a bar (c) positioned on top of the waveguide 370 at the center until de-bonding of one or more extraction elements occurs. The de-bonding may be partial or full de-bonding of an extractor element from the waveguide surface.

In some embodiments, a waveguide assembly having at least one reinforcement member coupled thereto does not exhibit de-bonding of one or more extraction elements at flexural loads provided in Table III. In one embodiment, for example, a waveguide assembly having at least one reinforcement member coupled thereto does not exhibit de-bonding of one or more extraction elements at an applied flexural load of 15-50 pounds. Additionally, in some embodiments, a waveguide assembly having at least one reinforcement member coupled thereto does not exhibit deflection greater than mm at applied flexural loads provided in Table III. Reinforced waveguide assemblies described herein, in some embodiments, exhibit less than 5 mm deflection at applied flexural loads of 15-50 pounds or 20-45 pounds.

Any light sources not inconsistent with the objectives of the present invention can be employed with waveguide assemblies having one or more reinforcement members coupled thereto. Fluorescent and/or LED light sources, for example, can be used in the luminaire construction. LED light sources may comprise packaged LED chip(s) or unpackaged LED chip(s). LED elements or modules can use LEDs of the same or different types and/or configurations. The LEDs can comprise single or multiple phosphor-converted white and/or color LEDs, and/or bare LED chip(s) mounted separately or together on a single substrate or package that comprises, for example, at least one phosphor-coated LED chip either alone or in combination with at least one color LED chip, such as a green LED, a yellow LED, a red LED, etc. The LED module can comprise phosphor-converted white or color LED chips and/or bare LED chips of the same or different colors mounted directly on a printed circuit board (e.g., chip on board) and/or packaged phosphor-converted white or color LEDs mounted on the printed circuit board, such as a metal core printed circuit board or FR4 board.

In some embodiments, the LEDs can be mounted directly to a heat sink or another type of board or substrate. Depending on the embodiment, LED arrangements or lighting arrangements using remote phosphor technology can be employed as would be understood by one of ordinary skill in the art, and examples of remote phosphor technology are described in U.S. Pat. No. 7,614,759, hereby incorporated by reference.

In those cases where a soft white illumination with improved color rendering is to be produced, each LED element or module or a plurality of such elements or modules may include one or more blue shifted yellow LEDs and one or more red or red/orange LEDs as described in U.S. Pat. No. 7,213,940, hereby incorporated by reference. The LEDs may be disposed in different configurations and/or layouts along one or more edges of the waveguide body, as desired. Different color temperatures and appearances could be produced using other LED combinations of single and/or multiple LED chips packaged into discrete packages and/or directly mounted to a printed circuit board as a chip-on board arrangement. In one embodiment, the light sources can comprise any LED, for example, an XP-Q LED incorporating TrueWhite® LED technology or as disclosed in U.S. patent application Ser. No. 13/649,067, filed Oct. 10, 2012, now U.S. Pat. No. 9,818,919, entitled “LED Package with Multiple Element Light Source and Encapsulant Having Planar Surfaces” by Lowes et al., the disclosure of which is hereby incorporated by reference herein. In another embodiment, the light sources can comprise XQ-E LEDs.

Any of the embodiments disclosed herein incorporating LED light sources may include power or driver circuitry having a buck regulator, a boost regulator, a buck-boost regulator, a fly-back converter, a SEPIC power supply or the like and/or multiple stage power converter employing the like, and may comprise a driver circuit as disclosed in U.S. patent application Ser. No. 14/291,829, filed May 30, 2014, now U.S. Pat. No. 9,791,110, entitled “High Efficiency Driver Circuit with Fast Response” by Hu et al. or U.S. patent application Ser. No. 14/292,001, filed May 30, 2014, now U.S. Pat. No. 9,303,823, entitled “SEPIC Driver Circuit with Low Input Current Ripple” by Hu et al., incorporated by reference herein. The circuit may further be used with light control circuitry that controls color temperature of any of the embodiments disclosed herein, such as disclosed in U.S. patent application Ser. No. 14/292,286, filed May 30, 2014, now U.S. Pat. No. 10,278,250, entitled “Lighting Fixture Providing Variable CCT” by Pope et al., incorporated by reference herein.

In some embodiments, each LED element or module may comprise one or more LEDs disposed within a coupling cavity with an air gap being disposed between the LED element or module and a light input surface. In any of the embodiments disclosed herein each of the LED element(s) or module(s) can have different or the same light distribution, although each may have a directional emission distribution (e.g., a side emitting distribution), as necessary for coupling with the waveguide.

FIG. 43 illustrates a waveguide assembly comprising a reinforcing frame coupled thereto, wherein LEDs are arranged at edges of the waveguide body according to some embodiments. As illustrated in FIG. 43 , the reinforcing frame 371 is coupled to the waveguide assembly 372 at vertices 373 of the frame 371. Pins 375 are employed at the vertices 373 for guiding placement of the reinforcing frame 371 over the waveguide assembly 372 and coupling to a corner assembly described below. Apertures 376 in the reinforcing frame 371 for receiving the pins 375 can be oversized to inhibit or preclude binding due to thermal expansion and/or displacement of the frame 371 during assembly of the reinforced structure.

The frame 371 can also be spaced from the surface of the waveguide body 377 by one or more spacers, as described herein, to minimize undesirable optical losses and/or aberrant lighting distributions resulting from coupling events and/or scratches to the light emitting surface. LED arrays 380 are arranged at edges of the waveguide body 377. In the embodiment of FIG. 43 , an LED array 380 is arranged on each edge of the waveguide body 377. In other embodiments, one or more LED arrays 380 are arranged on less than all edges of the waveguide body 377.

FIG. 44 illustrates a sectional view of the waveguide assembly and reinforcing frame of FIG. 43 . Pins 375 pass through the reinforcing frame 371 and the waveguide body 377. A corner assembly 385 in an open configuration is also illustrated. A corner 377′ of the waveguide body 377 inserts into the corner assembly 385. LED arrays 380 arranged along the edges of the waveguide body 377 also terminate at the corner assembly 385. The corner assembly 385 also comprises apertures 386 for receiving pins, bolts or screws to complete coupling of the reinforcing frame to the waveguide assembly in conjunction with a top plate closing the corner assembly 385.

FIG. 45 is a top view of the corner assembly of FIG. 44 . Apertures 386 for receiving the pins, bolts or screws are located outside the waveguide body 377, thereby precluding these structures from disrupting optical properties and lighting characteristics of the waveguide assembly 377. This can enable the use of pins, screws or bolts of larger dimension for enhanced mechanical integrity of the reinforced assembly.

FIG. 46 illustrates the corner assembly of FIG. 45 wherein a top plate encloses the corner assembly. The top plate 390 comprises apertures 391 for receiving pins 375 as well as apertures 392 for receiving pins, bolts or screws 393 which terminate in apertures 386 of FIGS. 44 and 45 . Once in place, the top plate 390 locks the reinforcement frame 371 into place. In the present embodiment, all four vertices of the reinforced waveguide assembly comprise corner assemblies. In other embodiments, less than all vertices can comprise corner assemblies. Moreover, similar coupling mechanisms can be applied at sides of the waveguide assembly.

FIG. 47 illustrates integration of the reinforced waveguide assembly into a luminaire construction according to some embodiments. In the embodiment of FIG. 47 , the reinforced waveguide assembly 401 is coupled to a mounting frame 402. The mounting frame 402 can also accommodate one or more optical elements 403 external to the reinforced waveguide assembly 401. An external optical element 403 can be a lens or reflective surface. The mounting frame 402 may also accommodate drive circuitry and associated components 404 for the LEDs. Drive circuitry 404, for example, can comprise one or more drivers and/or current controllers for the LED arrays. Specific layout of drive circuitry and associated components can be dependent on several considerations including, but not limited to, the number and composition of the LEDs and desired lighting characteristics of the luminaire.

The foregoing reinforcement concepts are applicable to other bonded assemblies comprising surface features. An assembly, in some embodiments, comprises a plurality of discrete surface features bonded to a first plate, wherein at least one reinforcement member is coupled to the assembly at one or more locations to reduce deflection of the assembly under an applied flexural load while not altering the surface features or function of the assembly. In some embodiments, the surface features are also associated with a second plate resulting in bonding of the first plate and the second plate via the surface features. Suitable reinforcement members can include any reinforcement member described herein in relation to the bonded waveguide assemblies. In some embodiments, a reinforcement member can be a bar, rod or frame.

The surface features of the assembly define a bonding region with the first plate. In embodiments wherein a second plate is present, the surface features also establish a bonding region with the second plate. In some embodiments, one or more reinforcement members are coupled to the first plate and/or second plate outside the bonding region. For example, a reinforcement member may be coupled to the first plate and/or second plate along one or more edges of the bonding region. In some embodiments, a frame fully or partially surrounds the bonding region. A frame can have a clamping configuration coupling to the first plate and the second plate. In other embodiments, a first frame can be coupled to the first plate and a second frame coupled to the second plate. Adhesive can be applied along one or more edges of the bonding region. The adhesive can be used alone or in conjunction with another reinforcement member, such as a frame.

In some embodiments, the first plate is larger than the second plate. The first and second plates may also be different in other dimensions, such as thickness. Moreover, the first plate and the second plate can generally have the same shape. Alternatively, first and second plates can have different shapes. Surface features of the first plate can have a variety of morphologies. In some embodiments, the surface features are protrusions, indentations, ridges, channels or combinations thereof. The surface features can be arranged in one or more arrays or predetermined patterns. In other embodiments, the surface features can have a random arrangement. Bonded area between the first plate and the second plate can be less than 10 percent or less than 5 percent of surface area between the first plate and second plate. Such low bonded area can permit de-bonding under an applied flexural load in the absence of reinforcement member(s). Assemblies comprising reinforcement members described herein can be evaluated according to the three-point bend apparatus described in relation to FIG. 42 .

Bonded assemblies having the foregoing constructions find application in a variety of fields. In some embodiments, a bonded assembly is a component of a microfluidic device. The microfluidic device can be continuous-flow or droplet based. For example, surface features of a first plate can define one or more fluid flow channels of the device with the second plate serving as a membrane to enclose the channels. Reinforcing member(s) can be coupled to the first and/or second plates according to embodiments described herein to prevent de-bonding or delamination of the plates in response to various stresses including, but not limited to, fluid pressure fluctuations and/or flexure of the microfluidic device. The bonded assemblies find application to various macro-fluidic devices and other pressure sensitive fluidic devices in a similar manner.

Various embodiments of the invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention. 

What is claimed is:
 1. A luminaire comprising: a waveguide body having a curved surface and a face normal to the curved surface; a light extraction component comprising an array of light extraction elements disposed over the face of the waveguide body; and a plurality of light emitting diodes (LEDs) configured to emit light into the curved surface of the waveguide body and positioned such that the plurality of LEDs have differing radial angular positions along the curved surface for steering an azimuthal component of illuminance distribution patterns of the luminaire in conjunction with the light extraction component. 